Possible fungus on gills

I have two axolotols and one black one appears to have some fungus on its gills. The other, an albino, is very hard to tell - he could have some, but it might just be colouring.

There's a slight, white, "filament"-like coating on and around the gill feathers of the black one. He has been swimming/floating at the top of the tank quite a lot lately, and I don't know whether this is related to it.

The albino has occasionally scratched his gills with his back legs.

Neither have had a great appetite over the past 2 weeks, eating only sparingly.

Summer is coming on in Australia and the tank temperature is warming up during the days - at least it's a bit warmer than when it was winter.

I have tested ammonia, nitrate and nitrite levels and they're all fine.

What should I do? Is this an emergency or is it easy to cure?

Some pictures would be quite useful, so we could see if it is fungus.
If it's a fungal problem it should be easy to cure.
If it is a very mild case then water changes to keep the water parametes perfect will help the axolotl to heal. If it is an obvious case, then perhaps a bath in tap water without dechlorinator, or perhaps a tea bath, both of which are not as strong or irritating as a salt bath.

How old are your axolotls? You've mentioned that they are not eating much. Are they pooping? How much are they eating? Do they look as if they have lost weight.
You've mentioned that your darker axis is spending time near the top of the tank. Is it floating? Can it swim back to the bottom of the tank, or does it keep floating back up?

Sorry about all of the questions, but just trying to get as much information as possible to help diagnose the problem.
:happy:

I actually went to the local aquarium and they said a salt bath should be a last resort as, with the axies already stressed, it might stress them out further. There is a Fungus and Fin Rot Cure Solution from Australian Pet Supplies which I bought and they said should work.

I tipped it into the tank (exact measurement - 45ml for a 190L tank) and the results have been OK. It's hard to see closely whether the fungus has disappeared, as the tank is a dark lime green colour now, but it does look to me as if the fungus might be going away on both of them. I'll try feeding them tonight to see if their appetite is back. The black one is still floating near the top of the tank, but not quite as much as he was - he was basically doing it 24/7 before.

I am a bit concerned about the greenness of the water though - 24 hours after using the solution, it's still lime green in there. I've contacted the makers of the solution, but they haven't got back to me. Does anyone know what I should do here? Will the water clear by itself, or should I completely cycle it, and if so, how soon should I do this?

I would actually recommend using this Anti Fungus solution. My tank is still a tiny bit green over a week later, but I'm doing water changes and eventually it will fade and be cycled out. The solution has completely gotten rid of the axie's gill fungus though - very effective stuff, and no need for a possibly stressful salt bath.